Polymeric membranes are commonly used to seal flat or low slope roofs of commercial buildings. Such membranes may be made of a variety of thermoplastic materials including, without limitation, Polyvinyl Chloride (PVC), PVC Alloys or Compounded Thermoplastics such as Tripolymer Alloy (TPA), Thermoplastic Olefin (TPO), Chlorinated Polyethylene (CPE), and Ethylene propylene diene terpolymer (EPDM). The most common types of commercial roofing membranes are made of PVC or TPO. The invention may be described herein for the sake of clarity primarily within the context of TPO membrane roofing. It will be understood, however, that the invention is not limited to TPO roofing membranes but applies to any other type of membrane used to roof and waterproof commercial and other buildings having low slope roofs.
When roofing a low slope roof, webs of membrane material are rolled out on a roof and adhered or bonded along their seams to provide a waterproof barrier atop the deck of the roof. Commercial roofs virtually always have protrusions that project upwardly from the roof deck. Such protrusions include, for example, HVAC ducts, ventilation ducts, rectangular protrusions for skylights and other features, parapets, and others. Non-circular protrusions such as rectangular protrusions define outside corners where the edges of the protrusion meet the roof deck. Other protrusions, such as parapets, form inside corners where two walls of the parapet meet the roof deck. Other protrusions that form inside and outside corners also may be present. In order to seal the roof, these corners must be sealed against water penetration. Traditionally, roofers would fabricate corner patches in the field by cutting, trimming, and configuring a scrap piece of membrane material until it fit a particular corner. This is a time consuming process, requires skill, and sometimes does not result in a good fitting leak proof patch.
More recently, prefabricated outside corner patches have been developed for sealing outside corners of protrusions on a commercial roof. U.S. Pat. No. 8,161,688, owned by the assignee of the present application, discloses a radially scalloped outside corner patch that, when spread out, conforms to substantially orthogonal outside corners of a protrusion. Pending U.S. patent application Ser. No. 13/454,674, also owned by the assignee of the present application, discloses a universal outside corner patch that is designed to conform to non-orthogonal outside corners of a protrusion. The disclosures of these documents are hereby incorporated by reference in their entireties. Accordingly, the convenient sealing of outside corners, both orthogonal and non-orthogonal, defined by protrusions from a commercial roof has been addressed.
Inside corners have been a different story. For orthogonal inside corners (corners formed by two inside walls that meet that meet each other and the roof deck at 90 degree angles), corner patches are available that are molded with three orthogonal sides that fit against the orthogonal sides and roof deck of an inside corner. However, inside corners often are not orthogonal and traditional inside corner patches do not fit well. When a corner patch does not fit well, it can lead to leaks at these corners over time. In cases where an inside corner includes a surface at an angle of more than a few degrees difference from 90 degrees, traditional inside corner patches cannot be used at all. A need exists for a universal inside corner patch that can conform to non-orthogonal inside corners or inside corners where one or more walls forming the corner meets the other walls or the roof deck at an angle significantly different than 90 degrees. Such a universal inside corner patch should also be equally usable just like pre-molded patches to seal orthogonal inside corners. It is to the provision of such a universal inside corner patch and to a method of sealing inside corners that the present invention is primarily directed.